Abstract
Ureaplasma species, typically considered commensal organisms of the human urogenital tract, have been implicated in various urinary tract infections (UTIs), including the rare and challenging presentation of pyelonephritis. This case report describes a unique instance of pyelonephritis induced by Ureaplasma, characterized by a negative routine urine culture and a lack of response to empirical antibiotic treatment, highlighting the complexities associated with diagnosing and managing infections caused by atypical pathogens. A 50-year-old female presented to the emergency department with symptoms suggestive of UTI, including fever, vomiting, and dysuria. However, initial urine analysis was notable for pyuria while routine bacterial culture returned negative results, creating a diagnostic dilemma. Empirical treatment with third-generation cephalosporin was initiated. However, the patient's condition failed to improve, raising concerns about antibiotic resistance or atypical pathogens. Subsequent molecular diagnostics, precisely polymerase chain reaction (PCR), identified Ureaplasma urealyticum as the causative agent. This prompted a change in the treatment regimen to doxycycline, to which the patient showed significant clinical improvement. Physicians should be aware of Ureaplasma as a potential cause of pyelonephritis, especially in cases of culture-negative UTIs and when patients do not respond to standard empirical treatment. This case emphasizes the importance of considering atypical pathogens in differential diagnosis and the role of molecular diagnostic techniques in guiding appropriate management.